The present invention relates to agricultural flail choppers and, in particular, to single and multi-arm polyurethane defoliating flails for removing leaves and other above-grade foliage and roughage, prior to harvesting below grade tubers, such as sugar beets or potatoes.
Flail choppers are well known in the agricultural industry and are used in a variety of different applications. Many flails are used to harvest sugar beets and potatoes. The flails or knives are typically constructed from metal and exhibit a variety of shapes and sharpened edges. Some metal flails are mounted to lengths of chain. A bored mounting plate typically secures the foregoing flails to a rotating drum or arm. U.S. Pat. Des. Nos. 340,247 and 5,249,751 disclose two rigid metal flails.
Examples of two flexible, polyurethane flails are shown at U.S. Pat. Nos. 4,691,506 and 4,691,507. The latter flails include metal fingers and metal studs which are formed into the ends of the flails.
Conventional flails provide a single arm which extends from a mounting end, for example, a mounting plate or a tubular bore. Polyurethane flails and other known rubber flails merely provide a molded end having a transverse extending bore. Durability, thus depends upon the material, since wear occurs not only at the foliage striking end, but also at the mounting bore.
In various sugar beet harvesters, multiple flails are arrayed about the circumference of a supporting drum. The flails mount to a number of spokes or rods, which laterally extend between the ends of the drum. Each rod contains a number of laterally displaced flails, which pivot as the drum is rotated and shred encountered foliage. Different sizes and types of flails are frequently mounted at the drums. Spacers may be positioned between the flails as desired by the farmer and the crop being harvested. The vertical separation of the flails to the tuber being harvested and/or the ground is adjusted as necessary to optimize contact with the foliage, without damaging the tuber and preferably without contacting the ground.
The present invention discloses an improved resilient flail. In alternative, single and multi-arm constructions, the resilient arms radiate from a mounting hub containing a nylon bearing or rigid support bushing that is molded into the hub. The durometer of the arms is established to permit the arms to flex and conform to encountered foliage. The arms radially extend in coplanar, parallel relation or are radially offset.